In an effort to gain information about the genetic basis of antibody production and the structural localization and nature of the antibody-combining site, we plan to analyze the physicochemical properties and amino acid sequence of four monochonal immunoglobulins. Two of these proteins (BAZ, Sm) contain large deletions in the gamma polypeptide chain. Protein Sm also contains lambda-type L-chains which have an intramolecular deletion of 81 amino acid residues in the variable region. By application of amino acid sequence analysis, the nature, extent, initiation and termination of the deleted area will be defined. A third IgG protein has antibody-like activity to the vitamin riboflavin. The primary structure of the V-region of the molecule will be determined in order to characterize the antibody-combining site. This information will be necessary to interpret the X-ray crystallographic data. A fourth protein, a lambda-type Bence Jones protein, contains a substantial quantity of carbohydrate; the point of attachment of this moiety to the polypeptide will also be defined. BIBLIOGRAPHIC REFERENCES: Primary structure of a deleted human lambda-type immunoglobulin light chain containing carbohydrates Protein Sm gamma. Fred A. Garver, Lebe Chang, Joseph Mendicino, Takashi Isobe and Elliott F. Osserman. Proc. Natl. Acad. Sci. U.S.A. 72 (1975) 4559-4563. The inhibition of the primary interaction between I125 labeled human hemoglobin and rabbit anti-human hemoglobin sera: A sensitive radioimmunoassay technique. Fred. A. Garver and David W. Talmage. J. Immunol. Methods 7 (1975) 271-282.